Recombinant Adeno-associated virus (rAAV) vectors (also referred to as rAAV particles herein) have emerged as one of the most versatile and successful gene therapy delivery vehicles. A number of clinical trials successfully commenced recently (Mueller and Flotte, 2008; High, 2011; High and Aubourg, 2011; Mingozzi and High, 2011; Nathwani et al., 2011; Asokan et al., 2012) and patients diagnosed with lipoprotein lipase deficiency will now have an option to be treated with Glybera®, the first rAAV-based drug to win the regulatory approval of the European Commission. However, even though the industry is poised for the expansion into several application areas represented by orphan diseases, a simple and scalable rAAV production technology is still lacking.